Key dates in dispute between the CIA and senators

WASHINGTON — Senators accuse the CIA of spying on their work. The CIA accuses a Senate panel of stealing its documents. It's "a defining moment" that will determine whether Congress can fulfill its duty to watch over the nation's spy agencies, says Senate Intelligence Committee Chairman Dianne Feinstein.

Here's a chronology of events leading up to the senators vs. CIA showdown, based on Feinstein's description Tuesday:

___

2002: In response to the Sept. 11, 2001, terror attacks, the CIA begins its secret detention and interrogation program. Waterboarding, prolonged sleep deprivation, confinement in a dark, cramped box and other harsh techniques are used on high-level al-Qaida suspects at secret overseas prisons.

___

2005: Reports of inhumane treatment of detainees, labeled torture by many critics, are widely circulated. Congress reacts by passing the Detainee Treatment Act to prohibit cruel, inhuman or degrading treatment of any prisoner.

___

September 2006: Then-CIA Director Michael Hayden briefs the full Senate Intelligence Committee on the still officially secret detention interrogation programs for the first time, just hours before President George W. Bush publicly discloses their existence.

___

December 2007: The New York Times reveals that the CIA has destroyed dozens of videotapes of some of the CIA's earliest interrogations using waterboarding and other "enhanced interrogation techniques" on al-Qaida detainees. Hayden tells the Senate committee that detailed records of the interrogations still exist on paper. Two committee staffers spend months reviewing thousands of classified documents.

___

January 2009: President Barack Obama takes office and bans the harsh interrogation techniques, ordering the CIA's secret prisons closed. He later says waterboarding was torture.

___

March 2009: Senators on the Intelligence Committee find their staffers' finished review of the CIA's enhanced interrogation records "chilling," according to Feinstein, D-Calif., who says the methods "were far different and far more harsh" than the CIA had described. The committee, now under Feinstein's leadership, launches a comprehensive study and asks the CIA to turn over more documents.

___

2009: The CIA objects to bringing the classified documents to Capitol Hill. Then-CIA Director Leon Panetta and Feinstein agree that Senate committee staff will review the documents electronically at a secure facility leased by the CIA in Virginia. The Senate staffers are to use a "stand-alone computer system" that would be segregated from CIA computers and protected from access by CIA personnel. The senators agree to let the CIA vet each document beforehand — a time-consuming process because the release eventually will grow to 6.2 million pages.

___

Mid-2009: The CIA begins making thousands and thousands of documents available via computer to the Intelligence Committee staff. With no index or organization, Feinstein says, it was "a true document dump." The committee asks for a search tool to help sort through the information, and the CIA provides it.

___

February 2010: CIA personnel secretly remove roughly 870 pages from the electronic document dump that had previously been available to the committee staff.

___

Mid-May 2010: Another 50 or so pages are secretly removed from the secure computer system by the CIA.

___

Later in May 2010: Committee investigators notice that some documents are missing. The committee complains to the CIA, which first denies that anything was taken from the system and later contends that removal of the documents was ordered by the White House. Officials at the White House deny in such order. Feinstein complains to the White House and gets an apology from the CIA and assurances that it won't happen again.

___

At some point in 2010: Committee staff searching the computerized documents find an internal review conducted in 2009 and 2010 by CIA personnel summarizing and analyzing the materials that had been provided to the Senate panel. Those documents, now referred to as the "internal Panetta review," acknowledge "significant CIA wrongdoing," according to Feinstein. It's not clear why they were among the documents turned over to the committee.

Committee staffers print copies of the internal Panetta review and make electronic copies on their CIA-provided computer system for future reference.

___

Probably sometime in 2010: Most of the internal Panetta review documents are deleted from the CIA's computerized document dump. Senate staffers, busy with a flood of incoming documents, don't notice when the report disappears. They still have the copies they made.

___

December 2012: The Senate Intelligence Committee approves its classified 6,300-page study of the detention and interrogation program and sends its findings to the executive branch.

___

June 2013: The CIA responds. The agency agrees with some of the Senate's work but disagrees with important parts. The Senate panel is surprised to see that the CIA is disputing some findings that were clearly acknowledged in the agency's earlier internal review.

___

Later in 2013: Concerned about the disparity between the CIA's official response and its earlier internal review, Senate staffers spirit away a printed portion of the Panetta review and bring it to the committee's secure space in a Capitol Hill office building. Feinstein says it was the right thing to do because the documents are "significant and important to protect." They corroborate critical elements of the Senate committee's findings "that the CIA's official response either objects to, denies, minimizes or ignores," she says.

___

Late 2013: Feinstein asks the CIA to turn over its full, final version of the internal Panetta review, because the committee has only a partial document.

___

Jan. 15, 2014: In a secret emergency meeting, Director John Brennan discloses that the CIA has conducted a search of the Senate committee's computers at the secure CIA-leased facility. According to Feinstein, Brennan told her and the committee vice chairman, Sen. Saxby Chambliss, R-Ga., that the search included the walled-off network driving containing the Senate committee's work and its internal communications.

The CIA accuses committee staffers of obtaining the agency's internal Panetta review through unauthorized means and says its investigation will continue.

___

Jan. 17: Feinstein writes to Brennan objecting to any further CIA investigation of the Senate committee. Feinstein says the CIA may have violated the constitutional separation of powers and the Fourth Amendment.

___

Also in January: The CIA's inspector general, David Buckley, begins an investigation into the CIA's activities regarding the Senate. Feinstein says that Buckley has referred information about the CIA's conduct to the Justice Department for a possible criminal investigation.

___

Later in January: The CIA's acting counsel general parries with his own referral to the Justice Department, suggesting that Senate staffers might have committed a crime in accessing and transporting the internal Panetta review. Feinstein says she views this "as a potential effort to intimidate this staff, and I am not taking this lightly."

She notes that the CIA acting general counsel who made allegations against Senate staffers was previously the chief lawyer for the detention and interrogation program and is mentioned frequently in the Senate report.

___

Tuesday: Feinstein rises on the Senate floor to condemn the CIA's conduct and call for public release of her committee's classified report.

"If the Senate can declassify this report," she says, "we will be able to ensure that an un-American, brutal program of detention and interrogation will never again be considered or permitted."

She also says that the way the allegations between the CIA and her committee are resolved will determine whether the panel can effectively monitor the nation's intelligence activities "or whether our work can be thwarted by those we oversee."

___

Later Tuesday: Brennan denies that the CIA spied on the Senate panel or made any attempt to thwart the Senate investigation. "That is not the case at all," he tells MSNBC.

White House spokesman Jay Carney refuses to take sides but says Obama has confidence in Brennan's leadership of the CIA.

Chambliss, the top Republican on the Intelligence Committee, says he disagrees with Feinstein about the dispute, without detailing his objections. He calls for a study "on what happened so people can find out what the facts are."